Helanthium Tenellum: Species Profile & Care Guide

Helanthium Tenellum

Helanthium tenellum, previously known as Echinodorus tenellus, is a freshwater plant commonly found in the aquarium trade, recognized for its delicate and grass-like appearance. It is native to North and South America, thriving in a wide range of environments from shallow waters to wet terrestrial areas. This adaptability makes it a favorite among aquarium enthusiasts for creating lush, carpet-like effects in the foreground of tanks. 

Helanthium tenellum is particularly valued for its ease of care and its ability to propagate quickly under the right conditions, which involve adequate lighting and nutrient-rich substrates. This plant exhibits a vibrant green color and produces runners that help it spread across the aquarium floor, offering a natural and aesthetically pleasing ground cover. Its resilience and attractive appearance contribute significantly to its popularity in aquascaping, where it’s used to create a sense of depth and to mimic natural aquatic landscapes.

Common Name(s)Pygmy chain sword, Narrow leaf chain sword
Scientific NameHelanthium tenellum (previously Echinodorus tenellus)
OriginNorth America
Ease of GrowingEasy to Moderate
AquascapeForeground, Carpeting plant
Height5-10 cm (2-4 inches)
Water pH6.5-7.5
Temperature22-28°C (72-82°F)
Growth RateModerate
Light RequirementMedium
CO2 RequirementLow to Medium (beneficial but not necessary)

Helanthium Tenellum Care

Helanthium tenellum is a popular freshwater aquarium plant well-regarded for its lush, grass-like appearance, making it an ideal choice for creating a natural or Iwagumi style aquascape. This plant is relatively easy to care for, thriving in a wide range of water conditions. It prefers moderate to high lighting to promote dense growth and a rich green color, although it can survive in lower light conditions at a slower growth rate. 

Helanthium tenellum benefits from a nutrient-rich substrate and occasional fertilization, which supports its rapid spreading through runners. It adapts well to different water parameters, making it suitable for both soft and hard water aquariums. Its ease of care and ability to create a carpet effect on the aquarium floor make it a favored option for both novice and experienced aquarists. Regular trimming helps maintain its shape and encourages the spread of new shoots, further contributing to its reputation as an easy-to-grow aquatic plant.

Lighting Requirement

Helanthium tenellum is a popular aquarium plant often used as a carpeting plant in aquascaped aquariums. It’s known for its grass-like appearance and relatively easy care, making it a favorite among both beginners and experienced aquarists. When it comes to lighting requirements, Helanthium tenellum is adaptable but does best under specific conditions to thrive and achieve its full potential as a carpeting plant.

Lighting Requirement:

  • Intensity: Helanthium tenellum prefers medium to high light intensity. This means it should be provided with about 30 to 50 micromoles of PAR (Photosynthetically Active Radiation) at the substrate level. In practical terms, this often translates to LED lighting rated between 0.5 to 1 watt per liter of water, depending on the efficiency of the light fixture and the depth of the aquarium. High light intensity encourages the plant to grow horizontally and stay compact, which is desirable for a carpeting effect.
  • Duration: The daily light duration should be around 8 to 10 hours. It’s crucial to maintain a consistent light schedule to prevent stress on the plants and to discourage algae growth. Using a timer for your aquarium lights can help maintain consistency.
  • Spectrum: A full spectrum light that covers the entire range of visible light (400-700 nm) with an emphasis on the red and blue parts is ideal for promoting photosynthesis and healthy growth. Lights marketed as “full spectrum” or those specifically designed for planted aquariums often meet these requirements.
  • Adjustments and Considerations: It’s important to monitor the plant and adjust the lighting as needed. Signs of too much light can include algae growth on the leaves or the substrate near the plants, while insufficient light may cause the plant to grow vertically instead of spreading out.
  • Supplemental CO2 and Nutrients: Under high lighting conditions, Helanthium tenellum will benefit from supplemental CO2 and a well-balanced supply of macro and micro-nutrients. This will support its rapid growth and help maintain vibrant health and coloration.

While Helanthium tenellum is relatively adaptable to different lighting conditions, providing medium to high light intensity, with a full spectrum and consistent daily duration, will significantly enhance its growth and appearance as a carpeting plant in your aquarium. Always observe your plants and adjust your care routine as necessary to keep them healthy and thriving.

Temperature & Water Parameters

Helanthium tenellum is a popular aquarium plant commonly used in the foreground of aquascapes due to its grass-like appearance. To ensure the best growth and health of Helanthium tenellum, it’s important to maintain optimal water parameters and temperature in your aquarium. Here are the general guidelines:


  • Optimal Range: 22°C to 28°C (71.6°F to 82.4°F).
  • This plant can tolerate a wide range of temperatures but thrives best within this range. It’s important to maintain a stable temperature to avoid stressing the plant.

Water Parameters

  • pH Range: 5.0 to 7.0.
  • Helanthium tenellum prefers slightly acidic to neutral water conditions. It can adapt to slightly alkaline water as well, but growth might not be as vigorous.
  • Carbonate Hardness (KH): 3 to 8 dKH.
  • This range helps stabilize pH levels without making the water too hard for the plant’s liking.
  • General Hardness (GH): 4 to 14 dGH.
  • Maintaining general hardness within this range ensures that the water has enough minerals for the plant’s growth without being too hard.

Additional Tips

  • Regular water changes and maintenance are essential to remove excess nutrients and prevent algae growth.
  • Fertilization can be beneficial, especially if you’re not using a nutrient-rich substrate. Liquid fertilizers are recommended for water column feeders, and root tabs can be beneficial for root feeders like Helanthium tenellum.
  • Substrate: Nutrient-rich. A nutrient-rich substrate is beneficial for root development. Fine, sandy substrates allow for easier root spread and can support denser growth.
  • Water Movement: Moderate. Gentle to moderate water movement helps distribute nutrients and CO2 evenly, but strong currents should be avoided to prevent stress on the delicate leaves.

Ensuring these conditions will help your Helanthium tenellum thrive, creating a beautiful, carpeted look in your aquarium. Adjustments might be needed based on your specific setup and the needs of other inhabitants in your aquarium.

Growth Height & Growth Rate

Helanthium tenellum is a popular aquarium plant known for its grass-like appearance and is often used to create lush foreground carpets in aquariums. Here’s a brief overview of its growth height and growth rate:

Growth Height

  • Average Height: Helanthium tenellum typically grows to a height of about 2-10 cm (approximately 0.8-4 inches). However, under optimal conditions, it can grow slightly taller.
  • Conditions Impacting Height: Lighting, nutrient availability, and CO2 levels significantly affect its growth height. Under high light and with ample CO2 and nutrients, it tends to stay shorter and spread horizontally, creating a dense carpet. In lower light conditions, it may grow taller and less densely as it stretches towards the light source.

Growth Rate

  • Growth Rate: This plant has a moderate to fast growth rate, depending on the conditions provided.
  • Factors Influencing Growth Rate: Adequate lighting, CO2 supplementation, and a rich nutrient substrate are crucial for promoting faster growth and spread. It can adapt to a wide range of water parameters but thrives in soft to moderately hard water, with temperatures between 22-28°C (71.6-82.4°F).

Tips for Encouraging Growth

  • Lighting: Provide moderate to high lighting to encourage dense, low growth and faster carpet formation.
  • CO2 Supplementation: Adding CO2 can significantly enhance growth and vitality, helping the plant to spread more quickly. 
  • Nutrients: Use a nutrient-rich substrate and consider additional fertilization, especially if you observe signs of nutrient deficiency.
  • Regular Maintenance: Trimming the plant can encourage it to grow more horizontally, promoting a lush carpet effect.

Helanthium tenellum’s adaptability to different conditions and its appealing appearance make it a favored choice for aquascapers. With the right care, it can transform the foreground of an aquarium into a vibrant green carpet, adding depth and beauty to the aquascape.

Aquarium CO2 Requirement

Aquarium CO2 injection can be beneficial for many aquatic plants, including Helanthium tenellum. This plant is a popular choice for aquariums due to its carpet-forming ability, making it an excellent ground cover in planted tanks. Whether CO2 injection is necessary for Helanthium tenellum depends on several factors:

  • Growth Rate and Plant Health: CO2 injection can significantly enhance the growth rate and overall health of aquatic plants. It provides an essential resource for photosynthesis, leading to lush, vibrant growth. For Helanthium tenellum, CO2 supplementation can result in denser carpets and more vigorous growth.
  • Aquarium Lighting: The necessity for CO2 injection often correlates with the intensity and duration of aquarium lighting. High lighting conditions increase the demand for CO2, as plants photosynthesize more rapidly and thus require more carbon dioxide. If your aquarium has high lighting, adding CO2 can prevent CO2 from becoming a limiting factor in plant growth.
  • Aquarium Setup and Goals: If your goal is to achieve a densely planted, high-tech tank with rapid growth and vibrant plant colors, CO2 injection is beneficial. However, for low-tech setups with moderate lighting and less demanding plants, CO2 injection might not be necessary. Helanthium tenellum can grow without added CO2, albeit at a slower rate and with potentially less density.
  • Nutrient Balance: CO2 should be part of a balanced approach to aquarium plant care that includes appropriate lighting, substrate, and fertilization. An imbalance (e.g., high light and nutrients but insufficient CO2) can lead to algae problems.
  • Tank Inhabitants: Consider the needs of your fish and other tank inhabitants. While plants benefit from CO2 injection, very high levels of CO2 can be harmful to fish. Monitoring and adjusting CO2 levels to ensure they are within a safe range for all tank inhabitants is essential.

In summary, while CO2 injection is not strictly necessary for the growth of Helanthium tenellum, it can significantly enhance its growth and appearance in more advanced, high-light aquarium setups. For more casual or low-tech setups, this plant can still thrive, albeit at a slower pace and with a potentially less dense appearance.

How to Use the Plant in an Aquascape

The compact size of Helanthium tenellum and ease of care make it suitable for a range of aquarium sizes and styles. Here are some guidelines on how to effectively use Helanthium tenellum in an aquascape:

Starting Out

  • Substrate: Helanthium tenellum prefers a nutrient-rich substrate. Consider using a commercial aquatic plant soil or adding root tabs to provide essential nutrients.
  • Planting: Plant small clumps of Helanthium tenellum about an inch apart to give them room to spread. Use tweezers for precise placement.
  • Lighting: This plant requires moderate to high lighting to thrive and achieve compact growth. Insufficient light can lead to leggy plants and poor carpet formation.

Care and Maintenance

  • CO2 Supplementation: While not strictly necessary, adding CO2 to your aquarium can significantly enhance growth rates and the overall health of the plant.
  • Trimming: Regular trimming is essential to maintain a dense, carpet-like appearance. Trim the taller shoots to encourage lateral growth and denser carpets.
  • Fertilization: Liquid fertilizers can complement root feeding, especially if your substrate is not nutrient-rich. Focus on formulations that include iron and other micro-nutrients.

Design Tips

  • Foreground Placement: Helanthium tenellum is ideal for foreground planting. It creates a beautiful, dense carpet that can highlight other elements of your aquascape.
  • Creating Depth: Planting Helanthium tenellum in the foreground and gradually increasing the height of plants towards the back of your tank can create a sense of depth and perspective.
  • Contrast: Use plants with different textures, heights, and colors to contrast with Helanthium tenellum’s fine, green leaves. For instance, darker or reddish plants in the background or midground can make the green carpet stand out more vividly.


Helanthium tenellum propagates easily by sending out runners. New plants will develop along these runners and can be separated and replanted elsewhere in your tank to expand the carpet or start new ones.

By following these guidelines, Helanthium tenellum can be a standout feature in your aquascape, offering a vibrant, natural-looking carpet that enhances the aesthetics of your aquarium. Remember, patience is key; it may take several weeks to months for a full carpet to establish, but the result is well worth the effort.

How to Propagate

Propagating Helanthium tenellum can be a rewarding process for aquarium enthusiasts. Here’s a step-by-step guide to help you propagate this beautiful plant:

  1. Healthy Plant Selection: Start with a healthy parent plant. Look for vibrant green leaves and a robust root system. A healthy plant is more likely to produce viable runners for propagation.
  2. Wait for Runners: Helanthium tenellum propagates through runners, which are horizontal stems that grow out from the base of the plant. Over time, the parent plant will naturally produce these runners. Patience is key, as this can take several weeks or months.
  3. Separation: Once a runner has developed and you see small plants (daughter plants) forming along it, you can propagate. Ideally, wait until the daughter plants have developed their own root systems and a few leaves. This makes them more likely to survive when detached.
  4. Cutting the Runners: Using a pair of sharp scissors or aquascaping tools, carefully cut the runner close to the base of the daughter plant. Be careful not to damage the parent plant, the runner, or the daughter plants.
  5. Planting Daughter Plants: Plant the separated daughter plants in the substrate of your aquarium. Use tweezers for precise placement. Plant them at least a couple of inches apart to give them room to grow and spread. The substrate should be nutrient-rich to support growth. Lightly cover the roots with substrate, but do not bury the plant too deep.
  6. Care After Propagation: Provide the newly planted daughter plants with adequate lighting and nutrients. Helanthium tenellum prefers moderate to high lighting conditions to thrive and spread. Consider adding a liquid fertilizer or root tabs to the substrate to encourage growth.
  7. Monitoring: Keep an eye on the planted daughter plants and the parent plant. Remove any dead or dying leaves to prevent decay in the tank. With proper care, the daughter plants will start to grow and eventually produce their own runners, continuing the propagation cycle.

Additional Tips

  • CO2 addition can enhance growth and health, but it’s not strictly necessary for Helanthium tenellum.
  • Regular water changes and maintaining water parameters within suitable ranges for your aquarium inhabitants will support the overall health of the plants.
  • Be patient, as propagation and growth can be a slow process, especially in the beginning.

Propagation of Helanthium tenellum is a straightforward way to expand your aquatic garden and create a lush, carpeted look in your aquarium. With proper care and conditions, you can enjoy the beauty and satisfaction of growing this plant in your aquatic environment.

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